318 ◾ Mobile Ad Hoc Networks: Current Status and Future Trends
12.3.2 External Routes
If an object wishes to communicate to another one on the same MANET, it uses ad hoc rout-
ing protocols to find suitable routes to reach it. But if it wants to communicate with hosts on the
Internet, it must first find external routes throughout its current gateway. Objects may recognize
external routes from internal routes in different ways [2]. e most popular is by verifying if the
destination address prefix belongs to the same MANET subnetwork. is is the recommended
way when implementing mobile IP since it helps to recognize them when they roam into different
subnetworks. One alternative method requires that the local gateway stores the registrations fro